Due to aging and multiple factors, supportive tissue degenerates. As a result, tissue malfunctions or causes pain. For example, an unsupported urethra leads to urinary stress incontinence. Degenerated intervertebral discs shift compressive loads to facet joints, causing strain and pain. Osteoporotic loss of bone matrix leads to collapse of the vertebral body, causing deformity and pain. In cosmetics, unsupported junctions between muscles form wrinkles. Acne causes the loss of epidermis and forms pits beneath the skin.
Injection of bulking agents, such as collagen, hyaluronate, polyethylene glycol, silicon particles, glass particles, Teflon particles and polyurethane particles, have been used or proposed to correct unsupported tissue of various kinds; but injections of these gel or particles can migrate or be metabolized or oxidized over time.